Problem: The arithmetic sequence $(a_i)$ is defined by the formula: $a_i = 5 - 5(i - 1)$ What is $a_{12}$, the twelfth term in the sequence?
Explanation: From the given formula, we can see that the first term of the sequence is $5$ and the common difference is $-5$ To find $a_{12}$ , we can simply substitute $i = 12$ into the given formula. Therefore, the twelfth term is equal to $a_{12} = 5 - 5 (12 - 1) = -50$.